ui: providers new design

[lily-de]

Purpose of this PR is to match the latest designs for modals and provider cards.

When you click on configure in the alpha-flagged settings page you can see the modal.

https://github.com/user-attachments/assets/6202e0ee-cd49-4114-88c4-c155652f9aaa

In a first follow up PR I will add the custom form for Ollama and catch up on any other provider configuration details that are in main.

In the next follow up PR I will clean up some convoluted logic here --

• Possibly using React Context more extensively to avoid prop drilling
• Separating the concerns of data, UI, and callbacks more clearly